Communication system



Jan. 5, 1943. A H. J. NICHOLS ET AL 2,307,153

COMMUNICATION SYSTEM Filed Aug. 17, 1940 '7 Sheets-Sheet l A T'TORNEY.

lJam. 5, 1943. H. J. NICHOLS x-:T AL 2,307,153

COMMUNICATION SYSTEM Filed Aug. 17, 1940 7 Shee'tS-Sheel 2 INVENTORJ www. /v/c/fow Jan. 5, 1943.

H. J. NICHOLS ET AL COMMUNICATION SYSTEM Filed Aug. 17, 1940 7 Sheets-Sheet; 3

ATTORN Jan- 5, 1943- H. J. NICHOLS ET AL 2,307,153

COMMUNICATION SYSTEM Filed Aug, 17, 1940 '7 Sheets-Sheet 4 ATTORNEY.

H. J. NICHOLS ET AL 2,307,153V

COMMUNICATION SYSTEM VFiled Aug. 17, 1940 '7 Sheets-Sheet 5 Jan.' 5, 1943.

H. JLNlcHoLs ET A1.

COMMUNICATION SYSTEM Jan. 5, 1943.4

Filed Aug. 17, 1940 FIGB.

7 Sheets-Sheet 6 .A TTORNEY.

Jan. 5, 1943. A H. J. NICHOLS ET AL 2,307,153

COMMUNICATION SYSTEM Filed Aug. 17, 1940 '7 sheets-sheet 7 u iNVENToRs Patented Jan. 5, 1943 Harryv J. Nichols and Henry L. Tholstrup, Bing- 1 hamton, and John A. Skinner, Johnson City,

N. Y., assignors to International Business `Machines (Jorporation,l New York, N. Y., a

tion of New York Application August 17, 1940, Serial No; 353,112

24 Claims.

The present invention relates to interomce or interstation communication systems and morev particularly to communication systems for interconnecting separated typewriters oi a -certain standard construction wherein the operation fof one typewriter, in a normal manner, can either be isolated, at will, from the operation of the system to permit ordinary individual operation oi the typewriters or operation of the one typewriter in the normal manner can be utilized to'produce a copy, at a sending station, of the intelligence to be transmitted and to simultaneously actuate a second or receiving similar typwriter or a plurality of such receiving typewriters at remote points. Likewise, each of the plurality of receiving typewriters can be utilized as sending typewriters, if and when desired, and means are provided for signaling between stations so that selected stations, connected to the system, can, upon reception of a signal, be changed from an ordinary typing condition to a receiving condition. y

It is to be particularlyv noted, as will be exe plained in detail later, that upon conditioning a machine to send, the send conditioning means, which are electrically interiocked with the receive conditioning means, prevent operation of the receive means at a chosen sending machine and that upon conditioning the'other machine or machines to receive,.interlock means at said other machine or machines operate electrically to prevent operation of the sending means oi' the selected receiving stations, respectively.

In devices of the prior art wherein 'interoillce messages have been transmitted, special machines such as permutation bar printing telegraph devices, or teletype devices which are not the usual standard typing equipment of business oilices,

have been employed.

There have also been previously provided electrical interconnecting systems for standard typewriters but such systems have required either an extensive modification oi the mechanical structure of the typewriter itself, to adapt it to such systems; have required complicated, separate mechanical permutation bar devices for producing, under control of each character key, code. combinations oi signal impulses characteristic devices for receiving and inverting the received code signal, to select the one, corresponding, characterkey bar; or have required complicated electromechanical translator systems at the receiver, to produce. from the code signal transmitted, a selection of thetypebar corresponding to the typebar depressed at the transmitter.

Other systems for interconnecting typewriters have comprised means utilizing the well known start-stop principle including means producing signal code combinations in the well known cmponents are transmitted sequentially, or have comprised systems wherein the signal was composed of permutations of components, each diiferent in intensity, in character, in duration, or in electrical characteristics. While such 'systems have each provided certain features, desired and kobtained by the yparticular characteristic system utilized, they have not been characterized by simplicity.

Accordingly, one of the objects of the present tain standard typewriter which shall be a simpliof each keyboard character, along with similar 1 writers, is made possible.

A further object is to provide a novel system of communication for interconnecting two standard typewriters, comprising means controlled by depression of each key of the keyboard for setting up, in a simple and direct manner, a code signal combination of separate elements which combination varies with the function or character represented by the key depressed, said code combination comprising a plurality of electrical impulses or elements of identical characteristics and of equal duration, a conductor for each ele- 'ment oi' code, means for transmitting selectively and simultaneously over said conductors, the individual elements ofja character representing, code combinations tothereby greatly reduce the period required for signaling, as compared to the period required by start-stop signal systems utilizing sequentially transmitted code components, and electrical translator means controlled by the individual elements of the code combination :for selectively energizing, at a standard receiving typewriter, solely the operating solenoid of the key bar corresponding to the key depressed at the sending station, for operating said corresponding key bar, whereby the depression oi. a chosen character key of a standard typewriter, at one station, produces the typing of the selected character vat a remote station or stations by means of'a similar standard typewriter or type- Still another object is to provide a standard typewriter of the kind wherein power means is utilized to locally operate the typing elements, selectively, upon actuation of a chosen char- Baudot code and wherein a plurality of signal '60 acter key bar, means controlled by said power means for producing a code signal combination comprising a plurality of similar electrical signal elements, simultaneously transmitted, means including a similar standard typewriter of the power driven type at a remote station, means electrically translating said code signal combination of similar signal elements to select and Aelectrically condition the operating solenoid of the corresponding key bar at the remote station, and means including the code signal combination producing means, at the remote station, for resetting the electrical translator.

Another object is to provide means, including a standard typewriter, for setting up a code signal combination characteristic of a chosen key character of function comprising a characteristic combination of similar signal elements, simultaneously transmitted, a second standard typewriter, electrical means for individually operating the key levers of said second typewriter or producing a function thereat, switching means controlling the energization of each of said electrical means, a conductor for each element of code interconnecting said typewriters, an electrical translator comprising an electromagnet for each conductor, said magnets being selectively energized in accordance with the separate code signal elements comprising the character or function signal and said magnets selectively rendering operative, in accordance with the code signal, those switching means only which control the electric operating means of the corresponding key bar, or control performanceof a desired function, and means controlled upon reception of any combination for restoring the electrical translator to the condition existing prior to reception oi this code combination.

Still another object is to provide a system of communication including in combination a standard Electromatic" typewriter wherein the power drive of the typewriter simultaneously operates a chosen character type bar to type the chosen character and sets up, for transmission, a code signal permutation corresponding to the character selected, and receiving means comprising a second standard Electromaticf typewriter and including means controlled by the separate components of the signal permutation for electrically translating said signal to selectively operate only the character key corresponding to the character typed at the sending station and to clear the electrical translating means.

A further object is to provide a novel system of inter-oillce or interstation communication including at least a pair of standard typewriters having generally the usual keyboard, a series of solenoids, one for each character key, electrical connections between the respective typewriter solenoids including one conductive connection for each element of code and totaling in number less than the number of solenoids, means controlled by a selected key for simultaneously transmitting over selected ones of said conductive connections, separate elements of a signal permutation, the permutation of said elements corresponding to the character represented by the selected key, and electrical translator means comprising a relay for each conductive connection, selectively operated in accordance with the respective elements of the permutation and including a plurality of switch elements actuable into various cascade arrangements and controlled by said relays to assume a chosen cascade arrangement in accordance with the particular permutation for energizing the one key solenoid only, corresponding to the character key depressed at the sending station.

A further object is to provide, in a novel communication system including a plurality of standard typewriters, adapted to both send and receive electrical signals to selectively operate chosen key bars under the control of a remote instrument, control means for rendering one machine operative for sending, control means for rendering said machine operative for receiving, and interlock means. electrically operated, for automatically rendering one of these control means ineffective upon voperation of the other.

Still another object is to provide a novel system for interconnection of a plurality of typewriters to produce remote control ot one typewriter by another typewriter and to produce all typing functions including shift and shift-check, by setting controlled elements of one typewriter in response to signals from another, and means responsive to said remote control for resetting the controlled elements of the one typewriter after perfomance ot any function.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a diagrammatic view illustrating generally the tele-registering devices, such as typewriters. controlled by remotely originating signals, utilized in the novel system, and generally illustrating the means for electrical interconnection of the various tele-registering devices.

Fig. 2 is a diagrammatic view, partly in skeleton outline only, illustrating fundamentally how the operation of a type bar control key, at a sending station, produces a code signal permutation of separate elements, which in turn is electrically translated at a receiving station to actuate only, the corresponding type bar at the receiving station. 4

Fig. 3 is a wiring diagram of the novel electrical translator utilized in the present system and including the key bar solenoids and electrical connections between the translator and said solenoids.

Fig. 4 is a wiring diagram of one embodiment of a complete interconnecting system for signaling and for communication between a sending and a receiving typewriter.

Fig. 5 is a wiring diagram, partly in skeleton outline, of the receiving part of another embodiment oi' a communication system for interconnecting sending and receiving typewriters and including means for producing shift and shiftcheck and clearance of the electrical translator.

Fig. 6 is a wiring diagram of a variant of the system of Fig. 5.

Fig. 7 is a wiring diagram with a portion of one station omitted of a system embodying the several aspectsA of the present invention, as applied to three stations.

Referring to the drawings wherein like reference characters refer to like parts throughout the several views and more particularly to Fig. 1, the invention is illustrated in the present instance as applied to a pair of standard Electromatic typewriters A and B at the sending and receiving stations, respectively, but it is to be specifically understood that any type oi' standard typewriter can be connected, as in the present invention, and that any number of typewriters can be so interconnected.

Typewriter A comprises a standard Electrol matic typewriter wherein the type bars are the character is typed on the record sheet' I0, at

station A, and an electrical code signal, composed of a predetermined permutation o f similar com-l ponents is transmitted Via the respective code channel conductors of' multi-conductor cable II y and the relay box, which alsocontains the electrical translator, to the corresponding male contacts I2m of the multiple plug I3, segregated into a signalling or comm icating group 'SG and a supervisory control/group SCG. Contacts I2m are inserted, during inter-oilce or inter-station communication, into the corresponding female contacts I2f of a cable box Il. Each of the character keys of the typewriter utilizes a number of male contacts I2m, in accordance with its particular code permutation of signal components, so that'when the multiple plug I3 is electrically connected to the cable box I4 and plug I5 is inserted into the ordinary power socket, a

signal, comprising the respective permutation of components, is produced, upon depression of the cho'sen character or function keys, and these components are respectively transmitted simultaneously through the corresponding conductors comprising the several code channels, which conductors are diagrammatically illustrated,'along with the necessary power and supervisory control conductors, as comprising generally an interstation multi-conductor cable I6 extending to the corresponding female contacts I2f to be connected with the male contacts I2m and the corresponding conductors, respectively, in the multiconductor cable II, at machine B. All compovnents of the signal are simultaneously transmitted through the interstation multi-conductor cable I6 so that not only are distributors at the sending and receiving ends eliminated, but the signal period, as compared to the signal period with the single wire` start-stop systems of the sequentially transmitted code component type, may be deilnitely diminished, permitting faster operation of the sending and receiving machines or the entire time cycle is made available for signalling, each code component thereby providing a signal impulse duration, several times that of a single channel printer of equal speed with a comparable ,time margin advantage. l

Furthermore, by the utilization of equal duration, entirely similar components of a, signal permutation, all special or complicated devices for measuring, utilizing or sorting the respective signal components are eliminated and an extremely simple translator of the type such as illustrated in the copending application of Harry J. Nichols, Serial No. 353,115, led Aug. 1'7, 1940,

can be utilized to translate the received signal permutation, to select the corresponding key bar at the receiving machine. The various components of the signal transmitted from station A are simultaneously applied to such an electrical translator', comprising means responsive to individual signal components and movable, cascade arranged switch elements controlled thereby, whereby one chain or cascade only, of the switch elements, is selectively closed, in accordance with the particular code permutation of components corresponding to the particular character, so that the corresponding key bar at station B will be operated, as willmbe explained presently. "7

When it is desired to operate any machine, such as machine A, in the normal manner, characteristic oi' a standard typewriter and disconnected from the system entirely, and assuming that the machines are all disconnected from the interstation communication system, the toggle switch Ta uatl the sending station A, ,for example, is thrown to the "on. position, which closes a circuit to the motor oi' the typewriter A,'as will be explained in detail iny connection with Fig.,4, whereby the power roller of the machine is rotated, in the manner well known in the art. Typewriter A can thereupon be operated in the normal mannerby the operator at station A.

` Upon similar manipulation to the on position of the corresponding toggle switch Tb, at the machine B, the typewriter B can also be individually operated in the normal manner and neither the machine at station A nor the one at station B will interfere with or transmit tothe other.

When the operator at station A, however, wishes to send a message to station B, for example, to be simultaneously typed upon both machines, the operator at machine or station A, in order to warn station B, presses the make-switch, push button RBa at station A, which closes a circuit to the buzzer at station B, in a manner that will Vbe described in detail in connection with Fig. 4. To condition his machine to send to machine B, the operator at machine A presses the make-switch, push button SAa at station A, which conditions this machine and its associated circuits forsendi ing, all as will be described in detail in connection with Fig. 4. The send signal lamp SLa is lighted at station A to indicate to the operator at 1station A that machine A is in a sending condilon.

In order to place h is machine in condition for receiving, the operator atstation B, if his toggle switch Tb is already in the "on position, merely presses his make-switch, push button RBb, which conditions his machine for receiving, as will be described in detail later. The line lamps LL at all stations are thereupon lighted in the system of Fig. 4 to indicate that some one machine is in a receive condition and the receive signal lamp RLb at station B is lighted, indicating to the operator at station B'that, his machine is now in a receive condition.

Referring now to Fig.'2, the mechanism and circuits for the operation oi' a chosen character key at station A with the consequent mechanical typing of the selected character at the station A and the electrical typing of the same character at station B, are illustrated diagrammatically in skeleton outline only, in order to simplify the theory of operation. The arrangement for each electrical translator at both stations, which is indicated in skeleton outline only in Fig. 2, is illustrated in detail in Fig. 3, along with the electrical connections to the respective keyboard solenoids, as will be explained in detail in connection with Fig. 3.

The operation of a send conditioned machine to produce a signal for remote operation of a receive conditioned machine is as follows: upon deforce ol a return spring llc to move an extension arm I'Id, downwardly. Upon such downward movement. the biiurcated lower end of arm I'Id` engages a pin Ila on arm IIb, integral with apivoted stop lever Il, to rotate stop lever I l counterclockwise about its pivot |l. This rotation disengages a channel shaped lug Ild ct a stop lever Il from one oi' a pair oi' detenta Ita on power cam II. A pivoted impeller arm 20. in contact with an impeller lug Ilb on power cam I8, is constantly urged in a clockwise direction by means of a spring 2| and upon the disengagement o! the channel shaped lug Ild of'the stop lever, from a detent Isa of the cam, the impeller arm 20, by means of'its contact with impeller lug lib, rotates the cam It slightly, in a clockwise direction, until it engages the constantly Rotating power roller ISR. which 1s rotated about the stationary shaft ISS by means o! the typewriter motor ISM (see Fig. 4) in a manner well known in the art. The cam I9 by means of its contact with power roller I9R. is thereupon rotated a full halt revolution, clockwise, until the second detent Ia of the pair on cam I9 engages the channel shaped lug ld'oi stop lever I8, in a well known manner/y Cam I9 is pivotally mounted by its axis ISc upon one arm 22a of a bell-crank 22, in turn mounted for oscillation about pivot 22h, and upon such rotation of cam I9, its eccentric contour causes a lateral movement of the cam axis I9c to thereby oscillate bell-crank 22 in a counterclockwise direction. Such oscillation causes a downward movement of the arm 22e of bell-crank 22 l to in turn pull down a link 23 to rotate bell-crank 24 against the force of spring 25, to actuate link 26 to oscillate bell-crank 21 to in turn actuate the type bar 28 to strike one of the type characters 29 against the record III (see Fig. 1) in a manner well known in the art.

Operation of the power cam I9 is utilized to control the operation of a permutation unit, which unit may be of the type as illustrated in the copending application of Harry J. Nichols,

Serial No. 353,114, filed Aug. 17, 1940. The opis provided with a plurality of spaced studs car- I rled by the top and bottom bars Slt and SIB of selector 3| and extending outwardly and alternately from one side and the other of the selector member, successive studs on alternate sides being equally spaced. A complete set of seven out ci' a greater number of such studs, provided on any one selector member, is designated respectively as 3Ia, 3Ib, 3Ic, 3IUB, Bld, 3Ie and 3U in Fig. 2. Rotatably mounted on each of the code rock shafts 33a, 33h, 33e, 33UB, 33d, 33e, 33! and alternately on opposite sides of the selector member, are the diagrammatically represented rockshaft actuating clips 4. These clips are removably attached as disclosed in said copending application Serial No. 353,114, illed Aug. 1'7, 1940, the relative disposition of the clips in the assembly for each slider being dependent upon the particular code value ot the character, whose key controls the respective slider member. Upon depression of the chosen character key I1, the

rock-'shafts will be selectively rotated and in such a vdirection that switches controlled by the rockshafts, respectively, will be set up in accordance with the chosen character code value. It is to be particularly noted that the universal bail rock-shaft IIUB is always actuated, to4 thereby move one pair of its control contacts, momentarily out of engagement, while another pair is momentarily moved into engagement, rock-shaft UB being diagrammatically illustrated as spring biased by a spring 25 acting through its associated clip so that the rock-shaft is returned to its original position upon completion of the half revolution ofcam Il. l

.Upon the above described lateral movement of the cam axis Isc, therefore, the roller I0 moves slider 3| to the right against the force of spring 25 acting through the universal bail clip and stud SIUB, whereby the studs selectively actuate the associated clips, respectively, and rotate the universal bail rock-shalt 33UB and selectively rotate the remaining rock-shafts asrequired by the signal to be set up. Such selective actuation of the clips to rotate the associated rockshafts selectively, actuates the diagrammatically represented switch elements or lingers aI, bl, cI, UBI, dI, eI and f I, to move the self-spring-biased" universal bail switch arm UB2 out of engagement with one o! its coacting contacts 21a and into engagement with the other coacting contact UB, and to selectively move the switch arms a2, b2, c2, d2, e2 and f2 into or out oi.' engagement with the cooperating contacts a, b, c, d, e and f. respectively. It is to be particularly noted that all code signal permutation settings are diilerentially produced and only those rock-shafts are actuated which require a change from the setting for the previously typed character. II the same letter is typed twice in 'succession the corresponding slider is twice actuated but only the universal bail rockshaft is rotated a second time, since the remaining rock-shafts are retained in their previously set position by an associated detent pin 31d coacting with notches 3111. in the actuating elements and diagrammatically representing the lock means, as illustrated in Fig. 2, the actual construction and operation of the locking means being as described in detail in said copending application Serial No. 353,114, led Aug. 17, 1940.

As` diagrammatically illustrated in Fig. 2, the rock-shafts have been positioned by actuation of another slider into the positions as shown, in order to set up the code permutation representative of the letter e while upon actuation of the slider shown in Fig. 2 with its particular clip arrangement, as shown, the rock-shafts and associated switches will set up the switches in a permutation, representative of the letter v.

Each of the switch contacts a, b, c, d, e, and f, respectively, are connected bythe associated conductors a4, b4, etc. to the permutation contact points Pa, Pb, etc., respectively. A relay armature gang switch blade 3B is controlled by a permutation unit relay PUR to close a circuit from all the permutation contact points, respectively, through line 39 and terminal UBt, to the plus side of a D. C. source, via the bus bar BB, upon energization of the permutation unit relay, in a manner to be subsequently described.

Closure of a. circuit through contact point Pa and switch contact a is arbitrarily chosen as setting up the No. 1 element of the code permutation, while closure ora circuit through contact asomss point Pf and -switch contact f sets up the No. 8 element.

The switch arm UB is connected via line UBl to one side of the coli of the permutation unit relay PUR while the other side of said coil is connected, as shown in detail in Fig. 4, to the negative side of a D. C. power source, while switch contact 31a of the universal bail switch is electrically connected, via line 31h, to the terminal 31t of the electrical translator.

Each of the switch arms a2, b2, etc., and the universal bail contact UB2 are connected via conductors a3. b3, etc. and conductor UBI to the terminals at, bt, etc. and UBt, respectively, to which the code channel conductors AI, BI, CI, etc. and the `bus bar BB, respectively, are connected. Each of the lines a3, b3, etc. respectively are connected via lines a5, b5, cl, etc., respectively. to terminals a6, bB, etc., respectively, of the electrical translator.

The details of the electrical translator system in conjunction with the individual key solenoids oi' every character key, respectively, which may be of the type as illustrated in the above mentloned copending application, Serial No. 353,115, led Aug. 17, 1940, are illustrated in Fig. 3 and it is believed that a detailed description of the speciilc type. as shown, will clarify the operation oi the system, as illustrated in skeleton outline only, in Fig. 2.

Referring to Fig. 3, it is to be noted that basically, inv the system disclosed, selection of a particular item is secured, not by a step by step, successive halving method whereby one item only is selected from a given number, but in contradistinction to this, a givenJ number of items is divided into a number of groups, and one group of items, for example, is selected, generally by successive halving, and thereafter, one item from the chosen group is selected, by successive halving, or conversely, the selection of one item only, from each group, is tentatively selected, generally by successive halving, and thereafter, one item is chosen by selecting the particular group by successive halving. Such a system is characterized by great versatility, ,in that the number of groups of relays can be varied, as desired, within the scope of the particular code.

As disclosed in Fig. 3, a plurality of eight group relays GRI to GRB, inclusive, respectively, is provided, each relay having a pivoted armature 33 controlling a multiple contact controlling blade 40 for simultaneously opening and closing circuits through the relay contact points Ga, Gb, Gc, Gd, Ge, Gf, respectively, of the several group relays. Each relay contact point is illustrated as connected directly to a key bar solenoid, one solenoid being provided for each of the key characters of the keyboard and one for each key oi the keyboard controlling a desired function. Corresponding key solenoidsof each of the difierent groups are connected to the same bus bar, for example, the key solenoid connected to relay contact point Ga, of relay GRI, is connected to the bus bar IIGa, and the key solenoid connected to relay contact point Ga of GR2 is likewise connected to bus bar IGa, etc. Each of the bus bars terminates in the cascade'switch contacts Ia, IIb, llc, etc., respectively. Also connected to bus bar iGc, is the line 42, which in turn is connected to one of the iixed contacts, namely, LC of a typebasket contact switch BC, a movable blade II8 of which (see Fig. 5) is connected lby line 43 to a switch contact IIBC. The purpose of the typebasket contact switch is to enable a chosen permutation of signal elements to produce either a case shift or shift-check, a specinc example of which will be explained in detail, in connection with Fig. 5. All of the multiple contact blades 40 (Fig. 3) are conductively connected via bus bar 44 and b to one side .of a D. C. power source, as indicated in Fig. 3. The other side of the D. C. power source is connected to the blade 86h, comprising one of a series of gang operated chain switch arms, grouped in a. chain or cascade arrangement, and controlled by the respective selector relays SRS, SRI and SRI, as illustrated in Fig. 3.

Each of the selector relays SRA, SRE and SRS, respectively, simultaneously controls its armature and one or more gang connected chain switch arms, the corresponding armature closin'g a holding circuit through its associated relay upon energization of the relay. For example, upon reception of a plus, code signal componentat terminal f6, transmitted by a remote machine, as will be described in detail in connection with Fig. 4. a circuit is closed from terminal f6 to the selector relay SRG, through the coil of this relay, thereby energizing the same, to the binding post or terminal S and then (Fig. 4) to the negative side of the D. C. power source. Energization of the coil of SRS causes it to attract its corresponding armature S6a to close the following holding circuit: From the positive side of a D. C. power source, line UBS (Figs. 2 and 3), universal bail switch arm UB2 (diagrammatically illustrated as biased against contact 31a via the spring 35 of the universal bail), contact 31a, line 31h to terminal Slt, line 3Ic to slow acting, retard relay Rr (Fig. 3 only) thereby energizing this relay, line 31d to the bus 45 thereby applying plus to this bus. Since the coil of relay SRS is energized,

its armature Sta closes a holding circuit from bus' bar 45 through the coil of this relay to the terminal Sf, thereby holding the relay SRG energized after the signal component is removed from terminal f6. Relays SR4 and SRS may or may not be energized at the same time as SRG, depending upon the particular permutation of signal components of the signal representing the character to be typed or of the function to be performed. Selective energization of relays SRC, SRS and SRS produces selective actuation of the gang connected chain switch arms to thereby close a chosen chain or cascade arrangement of switch arms to pick, in accordance with the particular code permutation. a certain key solenoid from each one of the different groups controlled by the respective group relays.

During the selective energization of relays SRl, SRS and SRS, the selector relays SRI, SR2, SR3 'may be simultaneously selectively energized to control their associated gang operated-chain contacts to close a certain cascade arrangement of switch blades through the corresponding contacts in accordance with the particular code per-v mutation. By the operation ofthe selector relays SRI, SR2 and SR3, a kcircuit is closed from terminal 31t, line 3`Ic, armature Rra of the energized retard relay Rr, contact point Rrc, line 65a to contact SIb, thence through the certain cascade arrangement of switch bladesand contacts and the particular line corresponding to a certain chosen one of the group relays, as determined by the selective energization of selector relays SRI, SR2 and SR3, respectively, through the chosen group-relay and via bus bar 48 and line Mb to the negative side of the D. C. source,

thereby selectively energizing and operating one of the group relays. Since one associated key solenoid of each group relay has been-selected, by successive halving, by operation of selector relays SR4, SR and SRS, respectively, and since, as stated above the selector relays SRI, SR2 and SR3 have also, by successive halving, selected one group only, a circuit is closed from the plus side of the D. C. source tdswitch blade S612, through the particular cascade of switch arms selected by relays SRS, SRS and SR4, to the selected one of the contacts 4|a to 4|f, inclusive, respectively (or through 4IBC with shift or shift check), through the corresponding key solenoid of the particular group relay energized, to the particular one of the relay points Ga to Gf, inclusive, the armature switch blade 40 of the selected group relay, bus bar 44, linellb to the negative side of the D. C. power' source thereby energizing the selected key solenoid and operating the associated key bar, as will now be described.

Referring to Fig. 2, the operation of the device will be explained in connection with the selection and operation of a particular key. Assuming that y the operator at station A wishes to type the lower case character v, having a code permutation comprising the No. 2, No. 3, No. 4 and No. 5 signal components, and to transmit this code permutation of signal components to station B whereby the same character v will be typed on a machine at station B. The typewriters at both stations A and B are assumed to be in lower case position, the circuits to terminals Sa to Sf, inclusive, at station B, conditioned for receiving (see Fig. 4), are closed, so that relays SRI to SRS, inclusive, may be selectively energized at station B by the signal components received from station A, and the circuits to terminals Sa to Sf, inclusive, at statilon A, conditioned to send, are open, so that the relays SRI to SRG, inclusive, at station A cannot be operated by the signals emitted by station A, all as will be explained in detail in connection with Fig. 4. In accordance with the particular 6 unit code adopted, the letter v is represented by simultaneous, similar, electrical signal components, respectively designated as components or units No. 2, No. 3, No. 4 and No. 5 of the 6unit code signal. Upon depression of the selected character key I1 of the keyboard, which key is representative of the letter v, the letter v is typed 'at the local station A, as previously described, by means of the power driven cam I9 corresponding to the letter v. Simultaneously, the corresponding roller moves the associated selector member 3| to the right. It is assumed, for purposes of simplicity in explanation, that the selector member 3|, corresponding to the letter v is provided with the clips arranged as diagrammatlcally illustrated in Fig. 2, so that code signal components Nos. 2, 3, 4 and 5 will be produced by closure of the proper switches upon movement of selector 3| to the right while the universal bail will also be operated. Stud 3|UB mounted on selector element 3| rotates the switch .actuating ringer UBI counterclockwise against the bias of spring to thereby permit switch arm DB2 to move into engagement with switch contact UB. A circuit is thereupon closed (Fig. 2) from the positive side of the D. C. power source to bus bar BB, terminal UBt, line UB3,

Pa. to Pf, inclusive, thereby supplying plus to these contact points from bus bar BB.

Also upon movement of .sliderV element 3I to the right, stud 3|a engages the associated clip 34 so that switch actuating member aI releases switch arm a2 from engagement with contact a so that the No. l code component is not supplied. Stud 3|b engages its associated clip so that switch actuating member bI closes switch arm b2 against the contact b. A circuit is thereupon closed as follows: from the plus side of the D. C. power source. bus bar BB, terminal UBt, line 39, armature 38, contact point Pb, line b4, contact b. arm b2, line b3 to terminal bt thereby supplying a positive signal component at terminal bt, or in other words, the No. 2 code component is set up. Operation of switch actuating elements cI, dl and eI likewise set up the No. 3, No. 4 and No. 5 code components, respectively.

Stud 3 If, however, upon movement to the right due to actuation of slider 3|, does not operate the clip 34, so that the switch arm f2 remains out of engagement with its cooperating contact f and the No. 6 code element is not supplied, the permutation unit, therefore, being differentially operated, as stated above.

Upon depression of key I1 at station A, therefore, four signal components of equal intensity and similar characteristics are simultaneously transmitted from terminals bt. ct, dt and et, respectively, over code channel conductors BI, CI, DI and El, respectively, thereby supplying the No. 2, No. 3, No. 4 and No. 5 code signal components to the lines b5, c5, d5 and e5, respectively, at station B. These No. 2. No. 3 No. 4 and No. 5 components, respectively, are therefore transmitted to terminals h6, cB, d6 and e6, respectively, of the electrical translator, at station B.

Referring to Fig. 3, the code signal component at terminal h6 energizes, via line b1, the coil of selector relay SR2, the circuit continuing from terminal Sb, to the negative side of the D. C. source, as will be described later in connection with Fig. 4. Energization of SR2 attracts its armature S2a to thereby close a holding circuit from the bus bar 45 through armature 82a, the associated contact point, the coil of SR2 to the terminal Sb. Upon attraction of the armature S2a at station B, the associated, gang operated chain switch blades S2b and S2c are moved from engagement with one contact point into engagement with the other of the respective pairs. Selector relay SR3 is likewise energized in response to the code signal permutation corresponding to character v but, as noted above, the No. 1 code signal element is not supplied and therefore selector relay SRI remains deenergized. Upon energization of relays SR2 and SR3 with consequent transfer of their relay armatures and associated gang switch blades, and the switch blade SIb of relay SRI remaining in contact with contact point 48, the following circuit, including the selected cascade circuit, is closed as follows: from the bus bar BB to line UB3 at station B, switch arm UB! in its unoperated position (Fig. 3), contact 31a. line 31h, terminal 3'It, line 31e, through retard relay Rr, energizing this slow-acting relay, to bus bar 45, thereby supplying holding current, as above described, to the operated selector relays SR2 and SH3. Energization of relay Rr closes a circuit from terminal 31t, line 31e, armature Rra, contact point Rrc, line 45a, switch blade S b, contact 48. switch blade S2c, contact 50, contact blade S3d, contact 5|, line 52, the coil of group relay GRB, bus bar 48, line Mb. to the negative side of the D. C. power source. Group relay GRI is thereupon energized attracting its amature I! and moving the gang switch arm 40 into engagement with the associated contact points Ga to Gf, respectively, of group relay GRB.

Similarly, the simultaneous code signal component at terminald, via line d1, energizes the selector relay SRLggm/*esponding to the No. 4

. unit o f the signal co/de, attracting its armature Sla, closing its holding circuit and operating the associated gang switch blades Slb, Sic and Sid so that these blades are 'each moved out of engagement with one associated' contact point and into engagement with the other contact point of its respective pair. Likewise the code component at terminal e6 energizes selector relay SRE. corresponding to the No. unit of signal code, so that its armature Sa is attracted and its gang operated switch blades are transferred. Since the relay SRS is not energized in response to the code signal permutation, representative oi the letter u, the following circuit, including the selected cascade circuit, is closed: From the plus side of the D. C. source to switch blade Stb, contact 53, switch blade Sic, contact B4, switch blade Sic, contact llc, bus bar lIGc, terminal 55a, to the key solenoid 55 of group relay GRS, terminal 55h, contact point Gc, group relay switch arm 40 of group relay GRB, bus bar 44, line Mb, to thev negative side of the D. C. power source. In order to coordinate the circuits of Fig. 3 with the schematic skeleton diagram of Fig. 2, the solenoid 55 is illustrated as provided with the terminals 55a and 55h, it being noted that the selector relays SRI, SR2 and SR3 select, in response to the No. 2 and No. 3 code components, only the group relay GRE, to energize this relay to thereby move its arm 40 into engagement with the contact point Gc to thereby connect terminal 55h of solenoid 55 to the negative side of the D. C. power source. The relays SR4, SRS and SR6, in response to the No. 4 and No. 5 code components, close a predetermined cascade arrangement of switch arms to connect terminal 55a of solenoid 55 to the positive side of the D. C. power source.

Referring to Fig. 2, the closure of the circuits to connect the terminals 55a and 65h of the electrical translator at station B to the D. C.

as will be explained In detail in connection with Fig. 4, that upon such actuation of the operating nngers, no4 signals are transmitted from the station B since the PUR relay at station B cannot be energized while this station is conditioned to receive and, therefore. the armature I8 at station B cannot move into contact with the points Pa to Pf, inclusive, and therefore no power is available for signal transmission upon the actuation oi' the switch operating iingers to move their respective switch arms selectively into engagement with the associated contacts, respectively.

Upon` the above described movement of the selector slide 3|, at station B, to the right, the stud IIUB, however, oscillates the operating finger UBI in a counterclockwise direction against the bias oi spring 35 to thereby permit the switch arm UB2 to move out of engagement with contact 31a (Fig. 3) whereupon the holding circuits through selector relays SR2, SRS, SRl and SRE are broken thereby deenergizing the chosen group relay GRB and disconnecting the terminals 55a and lib of the selected key solenoid 65 from the source of D. C. energy. The electrical translator at station B, therefore, maintains all circuits for operating the type bars oi the machine at station B, until the selected type bar is operated, whereupon the electrical translator is cleared or returned to normal, to condition it for receiving the next signal. Although switch arm UB2, at station B, is moved into engagement with contact UB, a circuit is not closed through the permutation unit relay PUR. since station B is in a receive condition and the circuit leading from PUR to the negative side of the D. C. source is open at contact 64 as will be explained in connection with Fig. 4.

A chosen degree of overlap between the signal reception and the process of translation may be provided, as will be explained in detail in connection with Fig. 6, whereby the signal may be stored at the electrical translator at station B for a chosen period, as desired.

One embodiment of the novel system, for interconnecting a plurality of typewriters of standard construction utilizing one conductor for each element of code, is illustrated in Fig. 4. Various inter-station signalinf, lines are also provided whereby the operator at a first station can sepower source by means of the selector relays and lectively warn the operators at other stations,`

group relay chosen, as explained above, closes a circuit through selected solenoid to thereby energize the solenoid. The closure of these circuits to so connect these terminals is indicated generally only, in Fig. 2, the selector relays SRI, SR2 and SRS being diagrammatically illustrated as controlling the energization of one group relay designated generally as GR to connect a terminal 55h to one side of the D. C. source and the selector relays SRI, SRE and SRG selectively controlling the selection of and connection of a terminal 55a to the other side of the D. C. source.

Energization of key solenoid 55, at station B, attracts the solenoid plunger 55p to pull down on aplunger mounting spring 55s attached to the key bar I'la at the station B. Downward movement of the plunger 55p depresses a key bar I'Ia against the force of spring I'lc to cause rotation of the power cam I9 and consequent typing of the Y chosen lower case character v at station B. The rotation of the power cam I9, moves the roller 30 laterally to the right, at station B, thereby moving the associated selector member 3| laterally to the right to actuate its coacting switch operating lingers. It is to be particularly noted, however,

that the iirst station desires to transmit a message to be typed on the machines at the selected other stations, in order that the stations warned can condition their machines for receiving. Means are also provided whereby up'on conditioning the rst station for sending, the receiving mechanism thereat is automatically rendered ineffective, and at the second or other stations the conditioning thereof for receiving, automatically renders the sending apparatus at these receiving stations, ineffective.

The electrical translator, utilized in connection with the system of Fig. 4 is merely indicated in outline in Fig. 2 to indicate the system and translator interconnections. it being noted that the complete electrical translator system, including a diagrammatic representation of the controlled key bar solenoids, is disclosed in Fig. 3, as explained in detail above.

' Referring to Fig. 4, the system is illustrated as applied to a three station system but it is obvious that any desired number of stations may be interconnected in Athe manner shown. Each station is provided with means for placing it in condition for sending, means for rendering its receiving means inoperative upon such conditioning of the sending means, means for selectively calling a desired other station or stations, means for indicating that some one station is receiving, means at each station to indicate .that the machine at the station is in a send or in a receive condition, a permutation sending unit, such as was described in detail in connection with Fig. 2, the order of the code permutation switch elements, however, being reversed and the universal bail transposed to simplify the illustration, successive code switches being conventionally illustrated as alternately open and closed and an electrical translator is provided, of the type as was described in connection with Fig. 3. Various other elements and connections are provided, as will now be described in detail.

Each station is provided with a ,typewriter driving motor 19M for continuously driving in a well known manner the power roll ISR (see Fig.

2). Motor |9M is shown as connected to a source of A. C. power. Although D. C. can be utilized by slight changes in the set up.) The motor connection is as follows: One side of the A. C. power source, line 56, motor IBM, line 51, type switch Ta of station A, line 58 to the opposite side of the A. C. power source.

To place his machine in the typing condition, A operator merely closes the switch Ta. This energizes the motor ISM to rotate the power roll (Fig. 2), so that upon depression of any character key, the selected character can be mechanically typed at station A and a corresponding code permutation of signal components, representative of the character, will be produced, as

previously described, ready for transmission over the respective code channel conductors, in a manner now set forth.

In order to condition his machine for sending, the operator at station A presses a make,

switch SAa thereby completing the following circuit: from plus on bus bar BB, terminal UBt at station A, line UB3, make switch SAa, line 59, line 60, lthrough the coil of sending relay SdR, a short portion of line 6|, line 62, line 63 to the negative line NL thereby picking up the relay SdR and actuating the following circuits: The switch blade SdR2 controlled by SdR engages the contact point 64 thereby closing a partial circuit only, from the line NL, line 63, line 63a, switch blade SdR2, point 6l, line 66, the coil of permutation unit relay PUR, line UB4, to contact UB; so that upon actuation of the switch arm UBZ, brought about by depression of any character or function control key, the coil of lPUR will be energized by connection of contact UB to switch arm UB2, line UB3, break switch Da, line UB3 continued, terminal UBt, to plus on bus bar BB which bus bar is connected to the plus power line PL, as illustrated in Fig. 4.

The contact SdRI of SdR is moved into engagement with contact point 65 .to close the following holding circuit for the relay SdR: From plus on bus bar BB, terminal UBt, line UB3, the break push button switch Da for disconnecting the machine at station A only, line 61, the normally open armature switch blade SdRI, point 65, line 68, normally closed, gang operated switch blade RRS, point 69, line 10, resistor 1I, to the left on line 60, coil of SdR, a short portion of line 6i, line 62, line 63, to minus on line NL, thereby holding SdR energized on a reduced current.

A send signal lamp SLa is wired in parallel to the coil and holding circuit of SdR via the following circuit: From coil SdR, line 60, line 12,

lamp SLa. to the left in line 13, line 14 to thc negative line NL. 'I'he signal lamp SLa, therefore, is lighted whenever the coil of SdR is energized, thereby indicating to the operator at station A that his machine is in a sending condition.

In order for the operator at station C, for example. to be warned to condition his machine to receive the message to be transmitted from station A, the operator at A merely presses the make button of switch RCa, thereby completing the following circuit: From plus on bus bar BB, terminal UBt, switch RCa, line 15a, terminal RCI, line 15C from station A to station C, line 16 at station C, buzzer BZc at station C, line 13 at station C, line 14 to the negative power line NL. The buzzer at station C is actuated to warn the operator at this station that another station wishes to communicate with him so tha-t he will immediately place his machine in a receiving condition.

In order to condition his machine for receiving, C operator presses the make button of switch RCc which completes the following circuit: From plus on bus bar BB, line UB3 at station C, switch RCc, line 11e, up line 18, coil of receive relay RR at station C, line 6I, line 62, line 63 to minus on the negative power line NL, thereby picking up the receive relay RR at station C. When relay RR picks up, the following circuits are closed: Normally open switch blades RRI to RRS. inclusive, of the receive relay, move into engagement with their corresponding contact points, connecting the binding posts Sa to Sf, inclusive (connected, as shown to one side of each oi the coils of the selector relays), to the negative power line NL via the following circuit: From the relay switch blades, common line 19, down line 6|, line 62, line 63 to the negative power line NL.

Relay switch blade RR1 also closes, completing the following holding circuit for relay RR: from plus on bus bar BB, line UB3 at station C, break button switch Dc in the line UB3, along a short portion of line UB3 to line 61, normally engaged switch blade SdRI and contact 65a, line 80, normally open switch blade RR1 (now closed) contact 8l, line 62, resistor 83, line 84, up line 18, to the coil oi RR, line 6I, line 62, line 63 to the negative line NL, thereby holding the coil of RR energized on a reduced current.

Likewise switch blade RR8 is operated to break its engagement with contact point 69 so that the holding circuit for the coil of SdR is opened and the coil is deenergized, provided that it was, previously, energized and held closed. It is to be specifically noted that the sending relay SdR. which conditions a station for sending, and the receiving relay RR, which conditions a station for receiving, are electrically interlocked at any one station to render one inoperative whenever the other is operative. Relay RR is maintained energized provided that the relay SdR is deenerglzed and its switch blade 'SdRI is, therefore, in engagement with its contact point 65a whereby the holding circuit of relay RR, as traced above, is maintained closed. As soon as relay SdR is energized, the holding circuit for RR is broken at contact point 65a and the relay RR is deenergized.

On the other hand, if SdR is energized, it is maintained energized, provided that relay RR is deenergized and its switch blade RR8 is therefore in engagement with its contact point 69, whereby the holding circuit of relay SdR is main-- tained closed. Upon energization of either one of the relays SdR or RR, by means of its respective directly 4connected push button switch,

the other relayis automatically dropped out and rendered inoperative. 'i

Novel electrical interlock means are therefore provided whereby upon energization of the sending"- relay, the receive apparatus at a station is automatically rendered inoperative, and vice Versa.

cable wire 8l to all or the other signal lamps LL4 in parallel with the llamp LL at station C by means of the respective lines 86a connected to cable 8l thereby lighting all the signal lamps LL at all stations to indicate to all the operators that at least one station, having been called, has

' been conditioned to receive. In order to indicate to operator C that his station is conditioned to receive. the receive signal lamp RLc at station C is connected in parallel to the coil and holding circuit of relay RR as follows: From line 84 (from which plus is fed to the coil of RR through its holding circuit), down line 18, lamp RLc. line 'I4 to the negative line NL, 'thereby lighting lamp RLc to indicate that station C is in a receive condition.

In exactly the same manner, A can call any other station, such as station B, or station B can call either or both of stations A and C etc. After station A is placed in a sending condition and station C is placed in a receiving condition as described above, the message is communicated froml station A to station C by the depression of the individual character keys at station A whereby the message is typed locally at station A and the respective code permutations of signal components are transmitted from station A over the respective cable line conductors AI, BI, Cl, DI, El and Fl, all as described in detail in connection with Figs. 2 and 3, the respective components of the signal energizing, selectively, the,

selector relays SRI to SRG, inclusive, at station C, in accordance with the particular code permutation, whereby the corresponding character or the corresponding function solenoid is energized and the character key bar at station C or the function key bar thereat isdepressed to type the chosen character on the record l (see Fig. 1) at station C or to produce the result desired.

When the key bar at station C is depressed under the control of the corresponding solenoid, the universal bail contact UBZ is shifted away i from contact 31a (see Fig. 2, station B, for example) to thereby interrupt the holding circuit for the selector relays, as previously described in connection with Fig. 3. Also, while movement of the switch arm UB2 from contact 31a to contact UB partly closes a circuit which extends to one side only of relay PUR, since the station C is in-a receive condition and hence, the relay SdR (Fig. 4) is deenergized and switch blade SdRZ therefore is'not in contact with point 64, the line 66 (see also Fig. 2) leading to relay PUR will be open and relay PUR remains deenergized even though the arm UB! engages contact UB. Armature 38 at station C, therefore, is not atv tracted by PUR and remainsin an unoperated signal switch arms cl2-f2, inclusive, at station C does not close any circuits to any of the cable conductors AI to FI, inclusive, so that back circuits are eliminated.

If any operator, at any station, wishes to isolate his machine from the lsystem without affecting the others, he merely presses'his local drop out or break-switch button D, whereby the holding circuits for both relays RR and SdR are interrupted and the station is disconnected from the interstation communication system but remains in local typing condition, as long as its typing switch remains closed.

If the operator desires to clear the entire system relay set up, to interrupt all communication, he merely presses his system drop-out' or break-switch button B, the buttons Ba, -Bb and Bc being connected in series in the positive power line PL, whereby upon ldepression of any selected breakswitch button, all relays at all stations are dropped and all of the stations return to a local typing condition only, provided that the typing switches at the respective stations remain closed.

It is seen, therefore, that station A can call station C, that station C can be placed in a receive condition, that station A can transmit its message and at the completion thereof either station A or station C can disconnect its machine from the line or the entire communication system can be cleared, in preparation for any other in skeleton outline only, and including generally the circuits and construction utilized in conjunction with a system such as that of Fig. l4, for example; whereby shift and shift-check are produced and whereby the machine at the receive station is completely cleared after reception of signals and performance of thefunction represented by the signal, including that condition when 'a shift-check signal is transmitted and the machine at the receive station is already in proper case vso that no slidable selector member is operated. Under this set of conditions the receive machine is nevertheless cleared, after performance of the shift-check function.

The system of Fig. 5 is intended to be utilized with shift mechanism such as disclosed in the patent to Harry J. Nichols No. 2,049,468 granted August 4, 1936, wherein one depression yof the shift key, produced for example, as in the present application, by one energization of its key solenoid, produces a shift ofthe typewriter carriage from one case to another case, as for example, depression of the shift key by the shift key `solenoid operates the shift mechanism to shift the type basket from the normal or lower case position to the upper case position, while a later, second energization of the same shift key solenoid will cause a subsequent depression of the same shift key bar whereby the associated shift mechanism is operated to return the type basket to the normal or. lower case position.

The shift-check key on the other hand, has no associated key solenoid and is manually operative only, to shift, at the send station, its associated slidable selector member 3| (Fig. 2) to thereby produce, by operation ofthe associated switch arms, the particular code permutation of signal l components indicative of the shift-check funcposition and any operation of the permutation` The code signal permutation for the shift function, under the code utilized, comprises the following code components or units; Nos. 1, 2, 4 and 5 only, while the code signal permutation for the shift-check function comprises code components Nos. 1, 2, 4, 5 and 6 only.

Referring to Fig. 5, in addition to the novel shift-check and shift means'utillzed in these functions, an electrical translator generally similar to that disclosed in Fig. 3 is utilized, the electrical translator of Fig. 5, however, including an extra switch blade for each selector, relay. and a special circuit, including an extra or auxiliary switch arm controlled by the universal bail switch arm, is provided, whereby an additional holding circuit for the chosen group relay is supplied and the utilization of the retard relay of Fig. 3 is eliminated.

Assuming that a code permutation of signal components representative of the shift function has been produced by depression of the shift key at a distant station and consequent operation oi the associated selector member and associated switch arms, thereupon the respective code signal components Nos. 1, 2, 4 and 5 comprising the v shift signal are transmitted over the corresponding code channel conductors and received at the terminals a6, h6, d6 and e6, respectively, of Fig. 5. The selector relays SRI, SR2, SR4 and SRS, respectively, are thereupon energized so that their gang operated switch arms are selectively operated to select one group relay and to close the particular cascade circuit connection which produces selection of the shift solenoid. Upon energization of the selector relays SRI and SR2 the following circuits are closed: From plus on terminal UBt, line UB3, break switch Da, line UB3 continued, the universal bail switch arm UB2, contact 31a, line IM, shift-check relay armature Sh.CRI, contact point |05, bus bar |08, through the armatures Slal and S2al now attracted and their cooperating contact points, respectively, to

close the holding circuits for selector relays SRI and SR2, respectively, in a manner now well understood. Energization of selector relays SRI and SR2 having operated their respective gang operated switch blades and these blades being now held in position by the holding circuits of the selector relays, the following circuits are closed:

From plus on terminal U'Bt, line UBS, break switch Da, line UB3 continued, the universal bail auxiliary switch arm UBA, contact point |01, line |08, shift-check switch blade Sh.CR2, contact point |09 to bus bar IIU. Since armatures Sla2 and S2a2, respectively, are now connected to bus bar I I0, the following cascade circuit is closed:

From bus bar I I0, contact points I I Ia and II Ib, and switch blades SIaZ and S2a2 in parallel, to bus b'ir II5, switch blade SIb, contact point 49, switch blade S2b, contact point II2, switch blade S312, contact point II3, to group relay GR2, through the coil of this relay to bus bar 46, to the negative side of the D. C. power source. Group relay GRZ is therefore energized and its armature 39 is attracted to operate its gang switch blade I0. Y

Energization of the selector relays SR and SRS closes their holding circuits in the same manner as those of relays SRI and SR2 thereby operating their respective gang operated switch blades and closing the following cascade circuit: From bus bar IIII, contact points Illa, lIIb and switch blades Sla! and S5a2, respectively, in parallel, bus bar IIS, switch blade Stb, contact point blade Slc, contact point llc, bus bar "Gc, the shift solenoid Sh.S, contact point Gc of group relay Gr2, gang switch blade 40 of the group relay GR2, bus bar 44 to the negative side of the D. C. source. Energization of the shift solenoid Sh.S operates the shift key once, so that the shift mechanism changes the position of the type basket from the existing position to the other position. Upon the operation of the shift key, its associated selector element 3l (Fig. 2) is operated and the universal bail switch arm UB2 and the universal bail auxiliary switch arm UBA are moved from the position shown in Fig. 5. to the opposite position, thereby opening the printing circuit and the holding circuits for the selector relays and for the chosen group relay and completely clearing the electrical translator. The receive machine is therefore ready to receive the next function or type signal.

'Ihe machine at the distant station, for the next operation to be described, is assumed to be in upper case position. Upon operation of the shift-check key at the distant station, the associated selector element 3l (Fig. 2) is operated and the code permutation signal corresponding to the shift-check function is set up. This permutation comprises the Nos. l, 2, 4, 5 and 6 code signal components which are transmitted over the corresponding code channel conductors to the receive station. Referring .to Fig. 5, components Nos. l. 2, 4, 5 and 6 are received at terminals a6, b5, d6, e6 and f6, respectively, whereby the selector relays SRI, SR2, SRA, SRS and SRS are operated and their holding circuits are closed, as set out above. Energization of selector relays SRI and SR2 again closes a cascade circuit to select the group relay GR2 whereby its gang switch blade 40 is operated and moved into engagement with the contact point Gc. The machine at the remote station, it is noted, has been assumed to be in the upper case position while the machine at the receive station, it is seen by reference to Fig. 5, is also in the upper case position. Energization of the selector relays SR4, SRS and SRG-closes the following circuits: from plus on bus bar I I0, through the three contact points Illa, IHb, II4c and switch blades S4412, S5a2 and S5a2, respectively, in parallel, bus bar H5, switch blade S612, contact point II 1, switch blade Sib, contact point IIBC, line I3, switch blade I I8 of the basket, con tact group BC, upper case contact UC, line I I8, the coil of the shift-check relay Sh.CR to the negative side of the D. C. power source. It is to be particularly noted, that the receive machine, being also in upper case, there is an agreement in case between the remote machine and the receive machine and therefore no circuit is closed through any solenoid associated with lthe gang switch blade l0 of group relay GRZ or in other words the shift solenoid Sh.S is not energized. Since the shift solenoid is'not energized, its associated selector element 3| (Fig. 2) is not operated and the universal bail contact UB2 and the universal bail auxiliary contact UBA are not operated. In the absence of a device such as the shift-check relay Sh.CR, the electrical translator, therefore, would not be cleared.

As stated above, however, the shift-check relay is energized when the send machine and the receive machine are both in the upper case position or in other words when there is an agreement in case between the sending and receive stations, and upon such energization of the shift-check relay Sh.CR, the switch blades Sh.CRI and 53. switch blade S50, contact point 54. Switch Sh.CR2 thereof are moved out of engagement asomts with the contact points I and I", respectively. so that the printing circuit and the holding circuits for the selector relays and the chosen group relay are opened and the electrical translator is entirely cleared and made ready for reception of the next signal.

Assuming, however, that the type basket at the receive station, instead of being in the upper case position,as shown in Fig. 5, is in the lower case position, the following operation thereupon ensues: Upon reception of the'code signal components Nos. l, 2, 4, 5 and 6, selector relays SRI and SR2 are energized and their holding circuitsare closed so that group relay GRZ is selected and energized, as before, to thereby move its gang operated switch blade 40 into contact with the contact point Gc. Energization of selector relays SRI, SR5 and SRG, closes their respective holding circuits and operates their associated switch blades and the following circuits are thereupon closed: from plus on bus bar III), through the three contact points II4a, Illb, IIIc. and switch blades Slal, Sia! and SBaZ, respectively, in parallel, bus bar H5, switch blade Sb, contact point I I1, switch blade 85h, contact point IIBC, line 43, switch blade II8 of the basket contact group BC,

' lower case contact LC, line 42, bus bar IIGc. to

the shift solenoid- SILS, contact Gc of group relay GR2, blade l0, to the bus bar M and to the negative side of the D. C. power source. Energization of the shift solenoid Sh.S operates the shift key and-its associated selector element 3| (Fig. 2) whereby the vuniversal bail switch arm UB2 and the universal bail auxiliary arm UBA are moved, from the positions as illustrated in Fig. 5 to the opposite poslsions, thereby opening the printing circuit and the holding circuits to the selector relays and the chosen group relay GRZ, so that the receive machine is cleared in preparation for reception of the next signal.

Referring to Fig. 6, there is illustrated therein a modication of the system of Fig. 5 wherein the shift check relay is replaced by a drop relay, the universal bail auxiliary contact UBA of Fig. 5 is eliminated and an overlap between signal reception and translation is provided. Furthermore, it is to be particularly noted that the clearance of the electrical translator, in the system as illustrated in Fig. 6, is performed entirely by the drop relay and that the utilization of both the universal bail switch arm and its auxiliary switch arm, for this purpose, is completely eliminated.

Referring to the system of Fig. 6, and assuming again that the remote station is in upper case and that the code permutation of signal components corresponding to shift check is produced at the remote station so that these components are transmitted over the respective code channel conductors and that the code components Nos. l, 2, 4. 5 and 6, respectively, are received at terminals a6, h6, d6, e6 and f6, respectively, of the receive station, as indicated in Fig. 6, and that selector relays SRI, SR2, SRI, SRS and SRG are selected and energized. The following circuits are closed:

From plus on terminal UBt, line U33, breakswitch Da, line DB3 continued, to the universal bail switch arm UB2. It is to be particularly noted that in the system of Fig. 6, the universal bail switch arm UB2, in its unoperated position, rests against an insulated'stop 31, such asis diagrammatically illustrated for all the other switch arms controlled by a selector member (Fig. 4).

A circuit is also closed from line UB3 continued.v

line 866e, the drop relay switch arm DRI, contact point IIiBa to bus bar |08 whereby a holding circuit is closed, in a manner now well understood, for each of the operated selector relays SRI, SR2, SRI, SR5 and SRS.

A circuit is also closed from line UB3 continued, line Iota, drop relay switch. arm, DR2, contact point I 09a to the bus bar IIO.-

Operation of selector relays SRI and SR2 produces selection of and energization of the group relay GR2, in the same manner as described i connection with Fig. 5.

The energization of the selector relays SRI, SR5 and SRS closes the following circuits: From bus bar III), contact .points IIIc, IMb, Illa and switch blades S6a2, SM2, Sla2, respectively, in parallel, bus bar IIS, switchv blade Sb, contact point II'I, switch blade Sib, contact point HBC, line 43, center switch blade IIB of the basket, contact group BC, upper case contact `UC, line IIS, resistor IZIL'through the coil of drop relay DR to the negative side of the D. C. power source. 'I'he drop relay is a slow acting, slow release type of relay so that it operates slowly only, to attract the relay arms DRI and DR2, respectively, whereby the holding circuits for the selector relays and the chosen group relay, are slowly opened thereby providing an overlap between the transmitted code signal and code signal storage.

'Ihe electrical translator is, therefore, cleared and the receive station is in readiness to receive the next signal. It is to be particularly noted that the drop relay was energized via the circuit just traced because of the fact that the receive machine was in the same case position as the sending machine, namely, upper case, and that no further operation of the receive machine was needed and thatA the electrical translator was nevertheless cleared.

Assuming that the remote station is in upper case position but that the receive station, instead of being in the upper case position as shown in Fig. 6, is in lower case position so that the switch blade II8 is in contact with the lower case contact point LC, and hence that the receive machine and the remote machine are in disagreement as to case position. Upon trans'w mission and reception of the shift check code permutation of signal components and consequent energization oi' the selector relays SRI and SR2, the group relay GRZ is energizedas before, and the amature III of the group relay GRZ is moved against the contact point Gc. Upon operation of the selector relays SR, SRS and SRG' the following circuits are closed: From bus bar IIII, points IIIcII4b, Illa, and blades S6a2, S5112, SM2, respectively, in parallel, bus bar IIB, blade Sib, contact point I II, blade S5b, contact point CIBC, line '43, center switch blade II8, contact point LC, line 42. bus bar 4IGc,` the shift solenoid Sh..S, contact point Gc, gang switch blade 40 of group relay GR2, bus bar u, line b and through the coil of the drop relay DR to the negative sideof the D. C. power source.

Upon energization ofthe shift solenoid Sh:S the shift key at the receive station is operated and the receive station is thereby shifted to the upper case position and is thereby brought into agreement with the case position of the remote machine. While the selector element 3i (Fig. 2) at the receiving station is also operated to thereby move the universal bail switch arm UB2, this operation does not open the holding circuits on the selector relays or on the chosen group relay, as in the system of Fig. 5. Energization of the slow acting drop relay DR however, slowly operates the associated arms DRI and DR2 to subsequently open the printing circuit and the holding circuits of the selected relays and of the chosen group relay, so that an overlap between code signal transmission and storage is provided and. the electrical translator is completely cleared in preparation for reception of the next signal.

It is to be noted that upon reception of any typing signal at the receive station, in the system of Fig. 6, the proper cascade circuits are closed to select the corresponding character key solenoid and simultaneously the drop relay DR is energized through the circuit extending from the selected solenoid, its associated contact point and group relay gang switch arm 40, bus bar M, line b and through the coil of the drop relay DR to the negative side of the D. C. source thereby energizing the drop relay so that the printing circuit and the holding circuits of the selector relays and th chosen group relay are opened, -but only after' the chosen solenoid has been energized to operate its associated key bar.

'Novel means are therefore provided which operate independently of the mechanical operation of the typewriters, to produce, in an eilicient manner, both overlap and clearance of the electrical translator under any conditions of operation.

Referring to Fig. 7, there is disclosed therein a wiring diagram of a system utilizing the several aspects of the present invention. The system as disclosed in Fig. 'l is closely patterned after the system illustrated in Fig. 4, with the interconnection between the system and the electrical translator generally as illustrated in Fig. 6.

In the system as disclosed in Fig. 7, the receive relays of Fig. 4 are replaced, respectively, by two receive relays, RRa and RRb, relay RRa controlling the switch blades RRI to RRG, inclusive, and relay RRb controlling the switch blades RRI to R9, inclusive, the number of blades controlled by one relay being limited to produce the best operation as disclosed by actual experiment.

The send relays SdR of Fig. 4, wherein said relays control two movable switch arms only, are replaced by generally similar send relays controlling however, three movable switch arms, the additional switch arms controlling, in cooperation with the receive relays RRb, a circuit constituting a novel dim-bright, status indicating system whereby the selective conditions of the respective station circuits are indicated at any one station, as will be described in detail presently.

The resistors 'II of Fig. 4 are omitted, in the system of Fig. 7, so that the sending relay is held under full current instead of on reduced current, as in Fig. 4. On the other hand, each of the holding circuits for the selector relays SRI to SRG, inclusive, respectively, is provided with a resistor 'I la, whereby the selector relays are held on reduced current, after energization thereof in response to received signals, instead of on full current, as previously described in connection with the other figures. v

The novel dim-bright status indicating system comprises an individual line lamp LLa, LLb (not shown), LLc, respectively, at each one of the stations, each of these lamps being provided with a dim-bright resistor DBRa, DBRb (not shown). DBRc, respectively, in series therewith. Each circuit, including this resistor and one of the lamps in series, is controlled by a pair of contacts, which in tum are controlled by the send relay SdR, as will be explained presently. A pair of contacts controlled by the receiverelays RRb on the other hand, control the combination of a plurality of said series circuits, into parallel circuits, to produce a variation in the brightness of illumination of the respective lamps LLa, LLb and LLc, as will now be explained.

When the device at station A is conditioned for sending, the following circuit is closed through the lampLLa at this station: from plus on bus bar BB, terminal UBt, line UB3, line I2I, switch blade SdR3 closed against contact I22, line 88o. down line 86, through resistor DBRa. lamp LLa, resistor LLaR, line 13, line I4 to the negative line NL. A similar circuit is closed through each of the lamps LLb and LLc at stations B and C. respectively, by means of line 86a at station A. terminal LLt, line 81. and each of the lines 86a at stations B (not shown), and C, respectively. It is seen, therefore, that each of the lamps LLa, LLb and LLc is lighted at a dimmed brilliancy, since current is fed to each of the lamps through the single resistor DBRa at station A. This indicates, by the lowered brilliancy of the line lamps at all stations, that some one of the stations has been conditioned for sending, which is in direct contradistinction to the system of Fig. 4, wherein illumination of the line lamps indicate that some one station has been conditioned to receive.

When the receive relay RRb at station C, for example, is energized, as described above in connection with Fig. 4, a circuit in the system of Fig. 7 is closed as follows: from plus on bus bar BB, line UB3 at station C, line I2I, line |23, contact 85, switch blade RRS of receive relay RRb, line 86, resistor DBRc, lamp LLc, resistor LLcR, line 13, line 'I4 to the negative line NL. 'I'he lamps LLa, LLb and LLc are therefore now connected in parallel with the power source, through a pair of resistors DBRa, DBRc in parallel, instead of a single resistance as above, so that the total effective resistance is reduced and the line lamps LLa, LLb and LLc glow with increased brilliancy to indicate that one of the stations has been connected to the system, in a receive condition.

If station B is now switched to a receiving condition, the resistor DBRb (not shown), will be placed in parallel with resistors DBRa and DBRc, so that the total effective resistance through the lamps LLa, LLb and LLc is further reduced, thereby producing a higher intensity of illumination of the indicating lamps and indicating that the three stations are interconnected; one being connected in the send condition and the other two being connected in the receive condition.

Novel means are therefore provided whereby an indication is presented that one station is conditioned to receive and the same means are also utilized to indicate that another station or stations have been connected to the rst station and in condition to receive a message from the iirst station. Y

Novel systems are therefore provided for interconnecting a plurality of standard construction typewriters of the power driven type, for example, for send and receive. comprising a minimum number of code element channels 'with maximum signaling time whereby upon actuation of a chosen key at one typewriter, in the ordinary manner, a key solenoid of the corresponding key at receive typewriters, can be selectively energized, to -actuate the corresponding key bar at each oi the connected stations, and upon such actuation, repeat back is prevented and multiple back circuits are completely avoided.

l ineffective and multiple back circuits are prevented, and upon conditioning another machine for receiving, its sending mechanism is rendered ineiective and repeat back is prevented.

yNovel means are also provided for producing an overlap between translation ard the operating signal transmission, arid no.el means are provided for producing a shift-check and clearance ot the shift-check circuits or consequent operation of the shift mechanism to perform the function and to clear the circuits. Novel means are Valso provided for clearing the electrical translator upon performance of any function or typing operation.

While there has been shown and described and pointed -out the fundamental novel features of the invention as applied to a plurality of modiiications, it will be understood that various omissions and substitutions and changes in the form and Adetails of the devices illustrated and in their operation may be made by those skilled in the art, without departing from the spirit of the invention. It `is the invention, therefore, to be limited only as indicated by the scope oi' the following claims. A

What is claimed is: y

1 1. In a system of the character described, a iirst tele-printing device at one station, a plurglity oi' other tele-printing devices at other stations, respectively, cally operating each of said devices, respective- 1y, means for interconnecting said stations for interstation control, and means at each of said stations and operative at any chosen station for either selectively disconnecting said chosen station only, from said system, while maintaining said station locally operative or for simultaneously rendering all of said stations inoperative for all interstation control except from said chosen station.

2. In a rsystem of the character described, a ilrst tele-printing device at one station, a plurality of tele-printing devices at other stations, respectively, motor means for rendering each oi said'devices locally operative, means for selectively transmitting a warning signal from one station to each of the other stations, to call said stations,l means for rendering said called stationsoperative to receive messages from said rlrst tele-printing device and interconnecting all of said stations into a system for system message transmission and reception, means for rendering said first device operative for transmitting to said other devices, means controlled at each station for selectively disconnecting each'station from said system while maintaining the remaining stations connected for interstatlon communication, and means at each' station for simultaneously disconnecting all interconnections among all stations. i

3. In a system of the character described, a typewriter including means adapted to send signais for remotely operating a similar typewriter and means for receiving remotely originating signals to control the operation locally, means for conditioning said typewriter for4 sending, means for conditioning said typewriter to receive, independently operated manually manipumotor means for lo-k lated means for respectively operating said con'- 'l5 ditioning means, and electrical interlock means interconnecting said sending and receive conditioning means. said interlock means being electrically controlled to render said receive conditioning operating means inoperative upon manual operation of said send conditioning operatin means.

4. In a system oi the Acharacter described, a plurality oi typewriting machines at separate stations, each machine including means adapted to send signals for controlling the individual keys oi a remotely situated similar machine and means toA receive remotely orignating signals to locally, individually operate the keys oi said machine in response to received signals, and each machine including a keyboard, said rst means comprising means at each station for producing electrical signals comprising code combinations of signal elements, the particular combinations of which correspond respectively to diierent characters, said second means comprising electrical means for individually controlling the operation of the several keys ci the keyboards, respectively, a plurality of conductive connections between all of said typewriters, means for placing each of said machines in a send condition and for connecting said machine, respectively, and selectively to said conductive connections, means forplacing each oi.' said machines in a receive condition and for connecting said machines, respectively and selectively to said conductive connections, means for respectively operating said conditioning means, and electrical means interlocking said send and said receive conditioning means at each station, respectively, said interlock means being electrically operated to render said receive conditioning operating means inoperative upon operation of said send conditioning operating means.

5. In a system of the character described, a plurality oi' typewriting machines at separate stations, each machine including means adapted to send signals for controlling individual keys of a remotely situated, similar machine, and each including a keyboard, means to locally, individually operate the keys of said machine under the control of remotely originating signals, said rst means comprising means at each station for producing electrical signals .comprising code combinations oi signal elements, the particular combinations of which represent different characters, electrical translator means at each typewriter adapted to be controlled by received signal elements for selectively energizing the individual key operating means, a plurality of conductive connections between said typewriters, means for placing each of said machines in a send condition and for connecting each machine selectively to said conductive connections, respectively, means for placing each of said machines in a receive condition and for connecting each machine to said conductive connections, and including signal element controlled means for operating said electrical translator means and completing the connection of said machine to said conductive connections, means for operating said send and receive conditioning means, respectively, and means electrically controlled upon operation of said send conditioning operating means at one machine for rendering inoperative said receive conditioning operating means.

6. In a system oi the character described, a plurality oi typewriting machines at separate stations, each machine including means adapted to send signals for-controlling the individual keys 

